CRAB in MM

Q: What is the "CRAB" of Multiple Myeloma (MM)?

Answer: 

"CRAB" is an acronym "CRAB" to remember the essential features of the spectrum of MM, which is a disease of infiltration of plasma cells into the bone or organs, and damage from immunoglobulin deposition. The "CRAB" stands for

• Calcium elevation
• Renal insufficiency
• Anemia, &
• Bone disease

MM is a disease of the older population, and may go undiagnosed for many years, and many times comes to attention when acute complications happen after many years, such as spinal cord compression, kidney failure, or hyperviscosity. 

Audience should be aware that CRAB is just an acronym, can be present in other diseases, and should not be used as a diagnostic criterion as MM can present with other features too.

#electrolytes

#nephrology

#bone-disease

#hematology

References:

1. Kyle RA, Gertz MA, Witzig TE, et al. Review of 1027 patients with newly diagnosed multiple myeloma. Mayo Clin Proc 2003; 78:21.

2. Nakaya A, Fujita S, Satake A, Nakanishi T, Azuma Y, Tsubokura Y, Hotta M, Yoshimura H, Ishii K, Ito T, Nomura S. Impact of CRAB Symptoms in Survival of Patients with Symptomatic Myeloma in Novel Agent Era. Hematol Rep. 2017 Feb 23;9(1):6887. doi: 10.4081/hr.2017.6887. PMID: 28286629; PMCID: PMC5337823.

3. Rajkumar SV. Evolving diagnostic criteria for multiple myeloma. Hematology Am Soc Hematol Educ Program. 2015;2015:272-8. doi: 10.1182/asheducation-2015.1.272. PMID: 26637733.